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Hemthanon T, Promdonkoy B, Boonserm P. Screening and characterization of Bacillus thuringiensis isolates for high production of Vip3A and Cry proteins and high thermostability to control Spodoptera spp. J Invertebr Pathol 2023; 201:108020. [PMID: 37956858 DOI: 10.1016/j.jip.2023.108020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 11/04/2023] [Accepted: 11/10/2023] [Indexed: 11/15/2023]
Abstract
Bacillus thuringiensis (Bt) is an entomopathogenic bacterium that produces crystalline (Cry and Cyt) and soluble (vegetative insecticidal proteins or Vips) proteins during the sporulation and vegetative growth phases, respectively. Combining Cry and Vip proteins could delay insect resistance development and exhibit synergistic activity against various insect pests. This study aims to screen Bt isolates collected from Thailand for high Vip3A and Cry protein production levels and high thermostability to control Spodoptera spp. Among the selected Bt isolates with high target protein synthesis, Bt isolate 506 was found to be safe for further biopesticide formulation due to the absence of non-specific metabolite, as determined by the detection of thermo-stable β-exotoxin I based on biological assays and PCR analysis. Bt isolate 506 showed the presence of Cry1A, Cry2A, and Vip3A-type proteins identified as Cry1Aa45, Cry2Aa22, and Vip3A87, respectively. The insecticidal activity of whole culture extracts containing Vip3A and Cry mixtures and culture supernatants containing secreted Vip3A protein was evaluated against the second-instar larvae of S. exigua and S. frugiperda. The Bt isolate 506 showed high toxicity against both insects, and the insecticidal proteins produced by this isolate retained their activity after heating at 50 °C. This Bt isolate is a promising candidate for further development as a biopesticide against lepidopteran pests.
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Affiliation(s)
- Tharathip Hemthanon
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand
| | - Boonhiang Promdonkoy
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Phahonyothin Road, Khlong Luang, Pathumthani 12120, Thailand
| | - Panadda Boonserm
- Institute of Molecular Biosciences, Mahidol University, Salaya, Phuttamonthon, Nakhon Pathom 73170, Thailand.
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2
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Chen F, Pang C, Zheng Z, Zhou W, Guo Z, Xiao D, Du H, Bravo A, Soberón M, Sun M, Peng D. Aminopeptidase MNP-1 triggers intestine protease production by activating daf-16 nuclear location to degrade pore-forming toxins in Caenorhabditis elegans. PLoS Pathog 2023; 19:e1011507. [PMID: 37440595 PMCID: PMC10368266 DOI: 10.1371/journal.ppat.1011507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Pore-forming toxins (PFTs) are effective tools for pathogens infection. By disrupting epithelial barriers and killing immune cells, PFTs promotes the colonization and reproduction of pathogenic microorganisms in their host. In turn, the host triggers defense responses, such as endocytosis, exocytosis, or autophagy. Bacillus thuringiensis (Bt) bacteria produce PFT, known as crystal proteins (Cry) which damage the intestinal cells of insects or nematodes, eventually killing them. In insects, aminopeptidase N (APN) has been shown to act as an important receptor for Cry toxins. Here, using the nematode Caenorhabditis elegans as model, an extensive screening of APN gene family was performed to analyze the potential role of these proteins in the mode of action of Cry5Ba against the nematode. We found that one APN, MNP-1, participate in the toxin defense response, since the mnp-1(ok2434) mutant showed a Cry5Ba hypersensitive phenotype. Gene expression analysis in mnp-1(ok2434) mutant revealed the involvement of two protease genes, F19C6.4 and R03G8.6, that participate in Cry5Ba degradation. Finally, analysis of the transduction pathway involved in F19C6.4 and R03G8.6 expression revealed that upon Cry5Ba exposure, the worms up regulated both protease genes through the activation of the FOXO transcription factor DAF-16, which was translocated into the nucleus. The nuclear location of DAF-16 was found to be dependent on mnp-1 under Cry5Ba treatment. Our work provides evidence of new host responses against PFTs produced by an enteric pathogenic bacterium, resulting in activation of host intestinal proteases that degrade the PFT in the intestine.
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Affiliation(s)
- Feng Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Cuiyun Pang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Ziqiang Zheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Wei Zhou
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Zhiqing Guo
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Danyang Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Hongwen Du
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, People's Republic of China
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Pronk LJU, Bakker PAHM, Keel C, Maurhofer M, Flury P. The secret life of plant-beneficial rhizosphere bacteria: insects as alternative hosts. Environ Microbiol 2022; 24:3273-3289. [PMID: 35315557 PMCID: PMC9542179 DOI: 10.1111/1462-2920.15968] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/15/2022]
Abstract
Root-colonizing bacteria have been intensively investigated for their intimate relationship with plants and their manifold plant-beneficial activities. They can inhibit growth and activity of pathogens or induce defence responses. In recent years, evidence has emerged that several plant-beneficial rhizosphere bacteria do not only associate with plants but also with insects. Their relationships with insects range from pathogenic to mutualistic and some rhizobacteria can use insects as vectors for dispersal to new host plants. Thus, the interactions of these bacteria with their environment are even more complex than previously thought and can extend far beyond the rhizosphere. The discovery of this secret life of rhizobacteria represents an exciting new field of research that should link the fields of plant-microbe and insect-microbe interactions. In this review, we provide examples of plant-beneficial rhizosphere bacteria that use insects as alternative hosts, and of potentially rhizosphere-competent insect symbionts. We discuss the bacterial traits that may enable a host-switch between plants and insects and further set the multi-host lifestyle of rhizobacteria into an evolutionary and ecological context. Finally, we identify important open research questions and discuss perspectives on the use of these rhizobacteria in agriculture.
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Affiliation(s)
| | | | - Christoph Keel
- Department of Fundamental MicrobiologyUniversity of LausanneLausanneSwitzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative BiologyETH ZürichZürichSwitzerland
| | - Pascale Flury
- Crop Protection – Phytopathology, Department of Crop SciencesResearch Institute of Organic Agriculture FiBLFrickSwitzerland
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4
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Ju S, Chen H, Wang S, Lin J, Ma Y, Aroian RV, Peng D, Sun M. C. elegans monitor energy status via the AMPK pathway to trigger innate immune responses against bacterial pathogens. Commun Biol 2022; 5:643. [PMID: 35773333 PMCID: PMC9246835 DOI: 10.1038/s42003-022-03589-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Pathogen recognition and the triggering of host innate immune system are critical to understanding pathogen-host interaction. Cellular surveillance systems have been identified as an important strategy for the identification of microbial infection. In the present study, using Bacillus thuringiensis-Caenorhabditis elegans as a model, we found an approach for surveillance systems to sense pathogens. We report that Bacillus thuringiensis Cry5Ba, a typical pore-forming toxin, caused mitochondrial damage and energy imbalance by triggering potassium ion leakage, instead of directly targeting mitochondria. Interestingly, we find C. elegans can monitor intracellular energy status to trigger innate immune responses via AMP-activated protein kinase (AMPK), secreting multiple effectors to defend against pathogenic attacks. Our study indicates that the imbalance of energy status is a prevalent side effect of pathogen infection. Furthermore, the AMPK-dependent surveillance system may serve as a practicable strategy for the host to recognize and defense against pathogens. Bacillus thuringiensis toxin Cry5Ba triggers potassium ion leakage, causing mitochondrial damage and energy imbalance. C. elegans can monitor this intracellular energy imbalance via AMP-activated protein kinase to trigger innate immune responses.
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Affiliation(s)
- Shouyong Ju
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hanqiao Chen
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shaoying Wang
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jian Lin
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yanli Ma
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China
| | - Raffi V Aroian
- Program in Molecular Medicine, University of Massachusetts Chan Medical School Worcester, Worcester, MA, 01605-2377, USA
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Hubei Hongshan Laboratory, National Engineering Research Center of Microbial Pesticides, Huazhong Agricultural University, Wuhan, 430070, China.
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Lin Y, Briandet R, Kovács ÁT. Bacillus cereus sensu lato biofilm formation and its ecological importance. Biofilm 2022; 4:100070. [PMID: 35243332 PMCID: PMC8861577 DOI: 10.1016/j.bioflm.2022.100070] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 12/20/2022] Open
Abstract
Biofilm formation is a ubiquitous process of bacterial communities that enables them to survive and persist in various environmental niches. The Bacillus cereus group includes phenotypically diversified species that are widely distributed in the environment. Often, B. cereus is considered a soil inhabitant, but it is also commonly isolated from plant roots, nematodes, and food products. Biofilms differ in their architecture and developmental processes, reflecting adaptations to specific niches. Importantly, some B. cereus strains are foodborne pathogens responsible for two types of gastrointestinal diseases, diarrhea and emesis, caused by distinct toxins. Thus, the persistency of biofilms is of particular concern for the food industry, and understanding the underlying mechanisms of biofilm formation contributes to cleaning procedures. This review focuses on the genetic background underpinning the regulation of biofilm development, as well as the matrix components associated with biofilms. We also reflect on the correlation between biofilm formation and the development of highly resistant spores. Finally, advances in our understanding of the ecological importance and evolution of biofilm formation in the B. cereus group are discussed.
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Gamage NW, Bamforth J, Ashfaq T, Bernard K, Gräfenhan T, Walkowiak S. Profiling of Bacillus cereus on Canadian grain. PLoS One 2021; 16:e0259209. [PMID: 34735500 PMCID: PMC8568128 DOI: 10.1371/journal.pone.0259209] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 10/14/2021] [Indexed: 11/18/2022] Open
Abstract
Microorganisms that cause foodborne illnesses challenge the food industry; however, environmental studies of these microorganisms on raw grain, prior to food processing, are uncommon. Bacillus cereus sensu lato is a diverse group of bacteria that is common in our everyday environment and occupy a wide array of niches. While some of these bacteria are beneficial to agriculture due to their entomopathogenic properties, others can cause foodborne illness; therefore, characterization of these bacteria is important from both agricultural and food safety standpoints. We performed a survey of wheat and flax grain samples in 2018 (n = 508) and 2017 (n = 636) and discovered that B. cereus was present in the majority of grain samples, as 56.3% and 85.2%, in two years respectively. Whole genome sequencing and comparative genomics of 109 presumptive B. cereus isolates indicates that most of the isolates were closely related and formed two genetically distinct groups. Comparisons to the available genomes of reference strains suggested that the members of these two groups are not closely related to strains previously reported to cause foodborne illness. From the same data set, another, genetically more diverse group of B. cereus was inferred, which had varying levels of similarity to previously reported strains that caused disease. Genomic analysis and PCR amplification of genes linked to toxin production indicated that most of the isolates carry the genes nheA and hbID, while other toxin genes and gene clusters, such as ces, were infrequent. This report of B. cereus on grain from Canada is the first of its kind and demonstrates the value of surveillance of bacteria naturally associated with raw agricultural commodities such as cereal grain and oilseeds.
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Affiliation(s)
| | - Janice Bamforth
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
| | - Tehreem Ashfaq
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
| | - Kathryn Bernard
- Public Health Agency of Canada, National Microbiology Laboratory, Government of Canada, Winnipeg, Canada
| | - Tom Gräfenhan
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
- Public Health Agency of Canada, National Microbiology Laboratory, Government of Canada, Winnipeg, Canada
- * E-mail: (TG); (SW)
| | - Sean Walkowiak
- Canadian Grain Commission, Government of Canada, Winnipeg, Canada
- * E-mail: (TG); (SW)
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7
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Belousova ME, Malovichko YV, Shikov AE, Nizhnikov AA, Antonets KS. Dissecting the Environmental Consequences of Bacillus thuringiensis Application for Natural Ecosystems. Toxins (Basel) 2021; 13:toxins13050355. [PMID: 34065665 PMCID: PMC8155924 DOI: 10.3390/toxins13050355] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/10/2021] [Accepted: 05/13/2021] [Indexed: 12/30/2022] Open
Abstract
Bacillus thuringiensis (Bt), a natural pathogen of different invertebrates, primarily insects, is widely used as a biological control agent. While Bt-based preparations are claimed to be safe for non-target organisms due to the immense host specificity of the bacterium, the growing evidence witnesses the distant consequences of their application for natural communities. For instance, upon introduction to soil habitats, Bt strains can affect indigenous microorganisms, such as bacteria and fungi, and further establish complex relationships with local plants, ranging from a mostly beneficial demeanor, to pathogenesis-like plant colonization. By exerting a direct effect on target insects, Bt can indirectly affect other organisms in the food chain. Furthermore, they can also exert an off-target activity on various soil and terrestrial invertebrates, and the frequent acquisition of virulence factors unrelated to major insecticidal toxins can extend the Bt host range to vertebrates, including humans. Even in the absence of direct detrimental effects, the exposure to Bt treatment may affect non-target organisms by reducing prey base and its nutritional value, resulting in delayed alleviation of their viability. The immense phenotypic plasticity of Bt strains, coupled with the complexity of ecological relationships they can engage in, indicates that further assessment of future Bt-based pesticides' safety should consider multiple levels of ecosystem organization and extend to a wide variety of their inhabitants.
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Affiliation(s)
- Maria E. Belousova
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
| | - Yury V. Malovichko
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton E. Shikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Anton A. Nizhnikov
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
| | - Kirill S. Antonets
- Laboratory for Proteomics of Supra-Organismal Systems, All-Russia Research Institute for Agricultural Microbiology (ARRIAM), 196608 St. Petersburg, Russia; (M.E.B.); (Y.V.M.); (A.E.S.); (A.A.N.)
- Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia
- Correspondence:
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Pinos D, Andrés-Garrido A, Ferré J, Hernández-Martínez P. Response Mechanisms of Invertebrates to Bacillus thuringiensis and Its Pesticidal Proteins. Microbiol Mol Biol Rev 2021; 85:e00007-20. [PMID: 33504654 PMCID: PMC8549848 DOI: 10.1128/mmbr.00007-20] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Extensive use of chemical insecticides adversely affects both environment and human health. One of the most popular biological pest control alternatives is bioinsecticides based on Bacillus thuringiensis This entomopathogenic bacterium produces different protein types which are toxic to several insect, mite, and nematode species. Currently, insecticidal proteins belonging to the Cry and Vip3 groups are widely used to control insect pests both in formulated sprays and in transgenic crops. However, the benefits of B. thuringiensis-based products are threatened by insect resistance evolution. Numerous studies have highlighted that mutations in genes coding for surrogate receptors are responsible for conferring resistance to B. thuringiensis Nevertheless, other mechanisms may also contribute to the reduction of the effectiveness of B. thuringiensis-based products for managing insect pests and even to the acquisition of resistance. Here, we review the relevant literature reporting how invertebrates (mainly insects and Caenorhabditis elegans) respond to exposure to B. thuringiensis as either whole bacteria, spores, and/or its pesticidal proteins.
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Affiliation(s)
- Daniel Pinos
- Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, Burjassot, Spain
| | - Ascensión Andrés-Garrido
- Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, Burjassot, Spain
| | - Juan Ferré
- Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, Burjassot, Spain
| | - Patricia Hernández-Martínez
- Instituto Universitario de Biotecnología y Biomedicina (BIOTECMED), Department of Genetics, Universitat de València, Burjassot, Spain
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Manktelow CJ, White H, Crickmore N, Raymond B. Divergence in environmental adaptation between terrestrial clades of the Bacillus cereus group. FEMS Microbiol Ecol 2020; 97:5974271. [PMID: 33175127 DOI: 10.1093/femsec/fiaa228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 11/06/2020] [Indexed: 12/25/2022] Open
Abstract
The Bacillus cereus group encompasses beneficial and harmful species in diverse niches and has a much debated taxonomy. Investigating whether selection has led to ecological divergence between phylogenetic clades can help understand the basis of speciation, and has implications for predicting biological safety across this group. Using three most terrestrial species in this group (B. cereus, Bacillus thuringiensis and Bacillus mycoides) we charactererized ecological specialization in terms of resource use, thermal adaptation and fitness in different environmental conditions and tested whether taxonomic species or phylogenetic clade best explained phenotypic variation. All isolates grew vigorously in protein rich media and insect cadavers, but exploitation of soil or plant derived nutrients was similarly weak for all. For B. thuringiensis and B. mycoides, clade and taxonomic species were important predictors of relative fitness in insect infections. Fully psychrotolerant isolates could outcompete B. thuringiensis in insects at low temperature, although psychrotolerance predicted growth in artificial media better than clade. In contrast to predictions, isolates in the Bacillus anthracis clade had sub-optimal growth at 37°C. The common ecological niche in these terrestrial B. cereus species is the ability to exploit protein rich resources such as cadavers. However, selection has led to different phylogenetic groups developing different strategies for accessing this resource. Thus, clades, as well as traditional taxonomic phenotypes, predict biologically important traits.
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Affiliation(s)
- C James Manktelow
- Centre for Ecology and Conservation, University of Exeter, Penryn campus, Penryn, TR10 9FE, UK
| | - Hugh White
- Centre for Ecology and Conservation, University of Exeter, Penryn campus, Penryn, TR10 9FE, UK
| | - Neil Crickmore
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Ben Raymond
- Centre for Ecology and Conservation, University of Exeter, Penryn campus, Penryn, TR10 9FE, UK
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Genomics and Proteomics Analyses Revealed Novel Candidate Pesticidal Proteins in a Lepidopteran-Toxic Bacillus thuringiensis Strain. Toxins (Basel) 2020; 12:toxins12110673. [PMID: 33114565 PMCID: PMC7693509 DOI: 10.3390/toxins12110673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/12/2020] [Accepted: 10/20/2020] [Indexed: 11/17/2022] Open
Abstract
Discovery and identification of novel insecticidal proteins in Bacillus thuringiensis (Bt) strains are of crucial importance for efficient biological control of pests and better management of insect resistance. In this study, the Bt strain KhF, toxic for Plodia interpunctella and Grapholita molesta larvae, underwent genomics and proteomics analyses to achieve a better understanding of the bases of its pathogenicity. The whole-genome sequencing results revealed that the KhF strain contained nine coding sequences with homologies to Bt insecticidal genes. The lepidopteran toxic mixture of spores and crystals of this Bt strain was subjected to liquid chromatography and tandem mass spectrometry (LC-MS/MS) to assess the protein composition. The results of the proteomic analyses, combined with the toxin gene sequences, revealed that two of the main components of the crystals were two new candidate pesticidal proteins, named KhFA and KhFB. These proteins showed a similarity lower than 36% to the other known Bt toxins. The phylogenetic analysis showed that the KhFA and KhFB grouped with the newly denominated Xpp and Mpp (former ETX/Mtx) pesticidal protein groups, respectively. Altogether, this study has led to the discovery of two novel candidate pesticidal toxins in the lepidopteran toxic KhF strain.
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Roberto AG, Itzel-Maralhi CF, Lilia-Lizette GD, Yesenia RS, Abigail PV, Carlos OP, Maria-Cristina SD, Arturo RP. Biofilm Production by Enterotoxigenic Strains of Bacillus cereus in Different Materials and under Different Environmental Conditions. Microorganisms 2020; 8:microorganisms8071071. [PMID: 32709126 PMCID: PMC7409032 DOI: 10.3390/microorganisms8071071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/15/2020] [Accepted: 07/15/2020] [Indexed: 11/16/2022] Open
Abstract
Foodborne illnesses, such as infections or food poisoning, can be caused by bacterial biofilms present in food matrices or machinery. The production of biofilms by several strains of Bacillus cereus on different materials under different culture conditions was determined, as well as the relationship of biofilms with motility, in addition to the enterotoxigenic profile and candidate genes that participate in the production of biofilms. Biofilm production of B. cereus strains was determined on five materials: glass, polystyrene, polyethylene, polyvinylchloride (PVC), PVC/glass; in three culture media: Phenol red broth, tryptic soy broth, and brain heart infusion broth; in two different temperatures (37 °C and 25 °C), and in two different oxygen conditions (oxygen and CO2 tension). Furthermore, the strains were molecularly characterized by end-point polymerase chain reaction. Motility was determined on semi-solid agar. The B. cereus strains in this study were mainly characterized as enterotoxigenic strains; statistically significant differences were found in the PVC material and biofilm production. Motility was positively associated with the production of biofilm in glass/PVC. The sipW and tasA genes were found in two strains. The results of this study are important in the food industry because the strains carry at least one enterotoxin gene and produce biofilms on different materials.
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Affiliation(s)
- Adame-Gómez Roberto
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico; (A.-G.R.); (C.-F.I.-M.); (G.-D.L.-L.); (R.-S.Y.)
| | - Cruz-Facundo Itzel-Maralhi
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico; (A.-G.R.); (C.-F.I.-M.); (G.-D.L.-L.); (R.-S.Y.)
| | - García-Díaz Lilia-Lizette
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico; (A.-G.R.); (C.-F.I.-M.); (G.-D.L.-L.); (R.-S.Y.)
| | - Ramírez-Sandoval Yesenia
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico; (A.-G.R.); (C.-F.I.-M.); (G.-D.L.-L.); (R.-S.Y.)
| | - Pérez-Valdespino Abigail
- Laboratorio de Ingeniería Genética, Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México 11350, Mexico;
| | - Ortuño-Pineda Carlos
- Laboratorio de Ácidos Nucleicos y Proteínas, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico;
| | | | - Ramírez-Peralta Arturo
- Laboratorio de Investigación en Patometabolismo Microbiano, Universidad Autónoma de Guerrero, Guerrero 39074, Mexico; (A.-G.R.); (C.-F.I.-M.); (G.-D.L.-L.); (R.-S.Y.)
- Correspondence:
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Abstract
The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis, B. cereus, and B. thuringiensis, are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.
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13
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Tian L, Shi S, Ma L, Tran LSP, Tian C. Community structures of the rhizomicrobiomes of cultivated and wild soybeans in their continuous cropping. Microbiol Res 2020; 232:126390. [PMID: 31855689 DOI: 10.1016/j.micres.2019.126390] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/15/2019] [Accepted: 12/03/2019] [Indexed: 11/15/2022]
Abstract
Continuous cropping of soybean often causes significant declines in yields of soybean because of the outbreaks of soil-borne fungal diseases. It has been reported that wild crops often harbour a unique microbiome to benefit the host plants. Thus, it is necessary to find the different community structures of the rhizomicrobiomes associated with cultivated and wild soybeans in their continuous cropping. In this study, we simulated monocropping of cultivated and wild soybeans under greenhouse conditions to investigate the rhizomicrobiomes of both soybeans. Results indicated that the bacterial community structure still maintained a changing trend after four continuous planting seasons, while fungal community structure showed a stable trend as indicated by the high similarity in the fungal community structure between the third and fourth planting rotations in both soybeans. In addition, by comparing the continuous cropping of the two soybeans, we found different fungal groups in their rhizospheres between the wild and cultivated soybeans following each passage. Spizellomycetaceae was more highly enriched in the rhizosphere following cultivation of the cultivated soybean, while Chaetomiaceae and Orbiliaceae were more highly enriched in the rhizosphere of wild soybean. Taken together, results of this study suggested that although there was the same trend of stabilized fungal development in the rhizospheres of both soybeans, wild soybean rhizosphere had different fungal groups compared with that of cultivated soybean following their continuous cropping. The findings of this study may provide useful information for the farmers with regard to planting soybean, especially when they consider growing soybean in monoculture.
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Affiliation(s)
- Lei Tian
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Shaohua Shi
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China
| | - Lina Ma
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lam-Son Phan Tran
- Institute of Research and Development, Duy Tan University, 03 Quang Trung, Da Nang, Vietnam.
| | - Chunjie Tian
- Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun, 130102, China.
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14
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Zheng C, Yu Z, Du C, Gong Y, Yin W, Li X, Li Z, Römling U, Chou SH, He J. 2-Methylcitrate cycle: a well-regulated controller of Bacillus sporulation. Environ Microbiol 2019; 22:1125-1140. [PMID: 31858668 DOI: 10.1111/1462-2920.14901] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 11/26/2019] [Accepted: 12/16/2019] [Indexed: 12/23/2022]
Abstract
Bacillus thuringiensis is the most widely used eco-friendly biopesticide, containing two primary determinants of biocontrol, endospore and insecticidal crystal proteins (ICPs). The 2-methylcitrate cycle is a widespread carbon metabolic pathway playing a crucial role in channelling propionyl-CoA, but with poorly understood metabolic regulatory mechanisms. Here, we dissect the transcriptional regulation of the 2-methylcitrate cycle operon prpCDB and report its unprecedented role in controlling the sporulation process of B. thuringiensis. We found that the transcriptional activity of the prp operon encoding the three critical enzymes PrpC, PrpD, and PrpB in the 2-methylcitrate cycle was negatively regulated by the two global transcription factors CcpA and AbrB, while positively regulated by the LysR family regulator CcpC, which jointly account for the fact that the 2-methylcitrate cycle is specifically and highly active in the stationary phase of growth. We also found that the prpD mutant accumulated 2-methylcitrate, the intermediate metabolite of the 2-methylcitrate cycle, which delayed and inhibited sporulation at the early stage. Thus, our results not only revealed sophisticated transcriptional regulatory mechanisms for the metabolic 2-methylcitrate cycle but also identified 2-methylcitrate as a novel regulator of sporulation in B. thuringiensis.
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Affiliation(s)
- Cao Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China.,Hubei Province Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables, College of Life Science and Technology, Hubei Engineering University, Xiaogan, Hubei, 432000, People's Republic of China
| | - Zhaoqing Yu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Cuiying Du
- Hubei Province Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hubei Key Laboratory of Quality Control of Characteristic Fruits and Vegetables, College of Life Science and Technology, Hubei Engineering University, Xiaogan, Hubei, 432000, People's Republic of China
| | - Yujing Gong
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Wen Yin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Xinfeng Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Zhou Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Shan-Ho Chou
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
| | - Jin He
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, People's Republic of China
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15
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Peng D, Luo X, Zhang N, Guo S, Zheng J, Chen L, Sun M. Small RNA-mediated Cry toxin silencing allows Bacillus thuringiensis to evade Caenorhabditis elegans avoidance behavioral defenses. Nucleic Acids Res 2019; 46:159-173. [PMID: 29069426 PMCID: PMC5758910 DOI: 10.1093/nar/gkx959] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 10/09/2017] [Indexed: 11/14/2022] Open
Abstract
Pathogen avoidance behavior protects animal hosts against microbial pathogens. Pathogens have evolved specific strategies during coevolution in response to such host defenses. However, these strategies for combatting host avoidance behavioral defenses remain poorly understood. Here, we used Caenorhabditis elegans and its bacterial pathogen Bacillus thuringiensis as a model and determined that small RNA (sRNA)-mediated Cry toxin silencing allowed pathogens to evade host avoidance behavioral defenses. The B. thuringiensis strain YBT-1518, which encodes three nematicidal cry genes, is highly toxic to C. elegans. However, the expression of the most potent toxin, Cry5Ba, was silenced in this strain when YBT-1518 was outside the host. Cry5Ba silencing was due to the sRNA BtsR1, which bound to the RBS site of the cry5Ba transcript via direct base pairing and inhibited Cry5Ba expression. Upon ingestion by C. elegans, Cry5Ba was expressed in vivo by strain YBT-1518. Cry5Ba silencing may allow B. thuringiensis to avoid nematode behavioral defenses and then express toxins once ingested to kill the host and gain a survival advantage. Our work describes a novel model of sRNA-mediated regulation to aid pathogens in combating host avoidance behavioral defenses.
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Affiliation(s)
- Donghai Peng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Xiaoxia Luo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ni Zhang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Suxia Guo
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ling Chen
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, Hubei, China
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Repertoire of the Bacillus thuringiensis Virulence Factors Unrelated to Major Classes of Protein Toxins and Its Role in Specificity of Host-Pathogen Interactions. Toxins (Basel) 2019; 11:toxins11060347. [PMID: 31212976 PMCID: PMC6628457 DOI: 10.3390/toxins11060347] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 05/21/2019] [Accepted: 06/10/2019] [Indexed: 12/28/2022] Open
Abstract
Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as well as its host specificity, are commonly attributed either to proteinaceous crystal parasporal toxins (Cry and Cyt) produced by bacteria in a stationary phase or to soluble toxins of Vip and Sip families secreted by vegetative cells. At the same time, numerous non-toxin virulence factors of Bt have been discovered, including metalloproteases, chitinases, aminopolyol antibiotics and nucleotide-mimicking moieties. These agents act at each stage of the B. thuringiensis invasion and contribute to cytotoxic properties of Bt strains enhancing toxin activity, ensuring host immune response evasion and participating in extracellular matrix degeneration. In this review we attempt to classify Bt virulence factors unrelated to major groups of protein toxins and discuss their putative role in the establishment of Bt specificity to various groups of insects.
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Wan L, Lin J, Du H, Zhang Y, Bravo A, Soberón M, Sun M, Peng D. Bacillus thuringiensistargets the host intestinal epithelial junctions for successful infection ofCaenorhabditis elegans. Environ Microbiol 2019; 21:1086-1098. [DOI: 10.1111/1462-2920.14528] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/02/2018] [Accepted: 12/12/2018] [Indexed: 01/28/2023]
Affiliation(s)
- Liting Wan
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Jian Lin
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Hongwen Du
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Yulan Zhang
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Alejandra Bravo
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Mario Soberón
- Instituto de BiotecnologíaUniversidad Nacional Autónoma de México Apdo. postal 510‐3, Cuernavaca, 62250 Morelos Mexico
| | - Ming Sun
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
| | - Donghai Peng
- State Key Laboratory of Agricultural MicrobiologyHuazhong Agricultural University Wuhan 430070 Hubei People's Republic of China
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18
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Expression of
cry
genes in
Bacillus thuringiensis
biotechnology. Appl Microbiol Biotechnol 2019; 103:1617-1626. [DOI: 10.1007/s00253-018-9552-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 11/28/2018] [Accepted: 11/29/2018] [Indexed: 01/03/2023]
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Whole-Genome Analysis of Bacillus thuringiensis Revealing Partial Genes as a Source of Novel Cry Toxins. Appl Environ Microbiol 2018; 84:AEM.00277-18. [PMID: 29752275 DOI: 10.1128/aem.00277-18] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 05/05/2018] [Indexed: 12/20/2022] Open
Abstract
Despite the successful application of crystal proteins (Cry) from Bacillus thuringiensis as biological control agents against insects, there is an increasing demand to identify new Cry toxins having higher toxicity and broad-spectrum activity against insects and plant-parasitic nematodes. To find novel Cry toxins, we screened 100 whole-genome sequences of B. thuringiensis Surprisingly, in addition to full Cry toxins, we found partial sequences, such as typical N-terminal or C-terminal regions with conserved domains, widely distributed among 20 strains of B. thuringiensis In order to further elucidate the functions of partial genes, here, we selected a partial sequence from strain C15, having 28% similarity with the N terminus of Cry5Ba and lacking a typical C terminus, and denoted it Cry5B-like N terminus. This fragment when coexpressed as a fusion protein with the C terminus of Cry5Ba (N-C fusion protein) produces pyramidal crystals. A recombinant N-C fusion protein having a 50% lethal concentration (LC50) of 23.7 μg/ml severely affected the life span, growth, and survival rate of nematodes. Light microscopy showed damage to the intestine of nematodes, confirming the pathogenicity of the N-C fusion protein. Last, the green fluorescent protein (GFP)-labeled mutant Caenorhabditis elegans FT63 showed significant damage to the intestine upon feeding N-C fusion toxin compared to the control. These results imply that partial genes can be a source of new Cry toxins, and further understanding about functions of partial cry genes can help in the study of the evolutionary strategy of B. thuringiensis to produce the multidomain toxins.IMPORTANCE Genomic analysis revealed that coding sequences for N termini and C termini of crystal proteins are widely distributed in B. thuringiensis We found Cry5B-like N terminus, lacking typical C terminus, was unable to be expressed in wild-type strain C15. However, its fusion with the C terminus of Cry5Ba not only was successfully expressed but also exhibited activity against the nematodes. This study provides insight into a potential source for novel Cry toxins.
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Galié S, García-Gutiérrez C, Miguélez EM, Villar CJ, Lombó F. Biofilms in the Food Industry: Health Aspects and Control Methods. Front Microbiol 2018; 9:898. [PMID: 29867809 PMCID: PMC5949339 DOI: 10.3389/fmicb.2018.00898] [Citation(s) in RCA: 411] [Impact Index Per Article: 68.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/18/2018] [Indexed: 12/18/2022] Open
Abstract
Diverse microorganisms are able to grow on food matrixes and along food industry infrastructures. This growth may give rise to biofilms. This review summarizes, on the one hand, the current knowledge regarding the main bacterial species responsible for initial colonization, maturation and dispersal of food industry biofilms, as well as their associated health issues in dairy products, ready-to-eat foods and other food matrixes. These human pathogens include Bacillus cereus (which secretes toxins that can cause diarrhea and vomiting symptoms), Escherichia coli (which may include enterotoxigenic and even enterohemorrhagic strains), Listeria monocytogenes (a ubiquitous species in soil and water that can lead to abortion in pregnant women and other serious complications in children and the elderly), Salmonella enterica (which, when contaminating a food pipeline biofilm, may induce massive outbreaks and even death in children and elderly), and Staphylococcus aureus (known for its numerous enteric toxins). On the other hand, this review describes the currently available biofilm prevention and disruption methods in food factories, including steel surface modifications (such as nanoparticles with different metal oxides, nanocomposites, antimicrobial polymers, hydrogels or liposomes), cell-signaling inhibition strategies (such as lactic and citric acids), chemical treatments (such as ozone, quaternary ammonium compounds, NaOCl and other sanitizers), enzymatic disruption strategies (such as cellulases, proteases, glycosidases and DNAses), non-thermal plasma treatments, the use of bacteriophages (such as P100), bacteriocins (such us nisin), biosurfactants (such as lichenysin or surfactin) and plant essential oils (such as citral- or carvacrol-containing oils).
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Affiliation(s)
- Serena Galié
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Coral García-Gutiérrez
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Elisa M. Miguélez
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Claudio J. Villar
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
| | - Felipe Lombó
- Research Group BIONUC (Biotechnology of Nutraceuticals and Bioactive Compounds), Departamento de Biología Funcional, Área de Microbiología, University of Oviedo, Oviedo, Spain
- Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Oviedo, Spain
- Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain
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21
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Méric G, Mageiros L, Pascoe B, Woodcock DJ, Mourkas E, Lamble S, Bowden R, Jolley KA, Raymond B, Sheppard SK. Lineage-specific plasmid acquisition and the evolution of specialized pathogens in Bacillus thuringiensis and the Bacillus cereus group. Mol Ecol 2018; 27:1524-1540. [PMID: 29509989 PMCID: PMC5947300 DOI: 10.1111/mec.14546] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 02/06/2018] [Accepted: 02/20/2018] [Indexed: 12/20/2022]
Abstract
Bacterial plasmids can vary from small selfish genetic elements to large autonomous replicons that constitute a significant proportion of total cellular DNA. By conferring novel function to the cell, plasmids may facilitate evolution but their mobility may be opposed by co-evolutionary relationships with chromosomes or encouraged via the infectious sharing of genes encoding public goods. Here, we explore these hypotheses through large-scale examination of the association between plasmids and chromosomal DNA in the phenotypically diverse Bacillus cereus group. This complex group is rich in plasmids, many of which encode essential virulence factors (Cry toxins) that are known public goods. We characterized population genomic structure, gene content and plasmid distribution to investigate the role of mobile elements in diversification. We analysed coding sequence within the core and accessory genome of 190 B. cereus group isolates, including 23 novel sequences and genes from 410 reference plasmid genomes. While cry genes were widely distributed, those with invertebrate toxicity were predominantly associated with one sequence cluster (clade 2) and phenotypically defined Bacillus thuringiensis. Cry toxin plasmids in clade 2 showed evidence of recent horizontal transfer and variable gene content, a pattern of plasmid segregation consistent with transfer during infectious cooperation. Nevertheless, comparison between clades suggests that co-evolutionary interactions may drive association between plasmids and chromosomes and limit wider transfer of key virulence traits. Proliferation of successful plasmid and chromosome combinations is a feature of specialized pathogens with characteristic niches (Bacillus anthracis, B. thuringiensis) and has occurred multiple times in the B. cereus group.
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Affiliation(s)
- Guillaume Méric
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
| | | | - Ben Pascoe
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
- MRC CLIMB ConsortiumUniversity of BathBathUK
| | - Dan J. Woodcock
- Mathematics Institute and Zeeman Institute for Systems Biology and Infectious Epidemiology ResearchUniversity of WarwickCoventryUK
| | - Evangelos Mourkas
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
| | - Sarah Lamble
- Wellcome Trust Centre for Human GeneticsUniversity of OxfordOxfordUK
| | - Rory Bowden
- Wellcome Trust Centre for Human GeneticsUniversity of OxfordOxfordUK
| | | | - Ben Raymond
- Department of Life SciencesFaculty of Natural SciencesImperial College LondonAscotUK
- Department of BiosciencesUniversity of ExeterExeterUK
| | - Samuel K. Sheppard
- The Milner Centre for EvolutionDepartment of Biology and BiochemistryUniversity of BathBathUK
- MRC CLIMB ConsortiumUniversity of BathBathUK
- Department of ZoologyUniversity of OxfordOxfordUK
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22
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Dissimilar Crystal Proteins Cry5Ca1 and Cry5Da1 Synergistically Act against Meloidogyne incognita and Delay Cry5Ba-Based Nematode Resistance. Appl Environ Microbiol 2017; 83:AEM.03505-16. [PMID: 28710264 DOI: 10.1128/aem.03505-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 06/09/2017] [Indexed: 01/20/2023] Open
Abstract
Cry proteins of Bacillus thuringiensis (Bt) have been successfully used as biopesticides and in transgenic crops throughout the world. However, resources against the most serious agricultural pathogens, plant root-knot nematodes, are limited. The genomes of several highly nematicidal virulent Bt strains from our laboratory have been sequenced, facilitating the identification of novel Cry proteins and other virulence factors. We identified two novel Cry proteins, Cry5Ca1 and Cry5Da1, that exhibit high toxicity against Meloidogyne incognita Using the Caenorhabditis elegans model, the two Cry5 toxins were shown to negatively affect nematode life span, fertility, and survival. The 50% lethal concentrations (LC50s) of Cry5Ca1 and Cry5Da1 were 57.22 μg/ml and 36.69 μg/ml, respectively. Moreover, a synergistic effect (synergism factor, 1.61 to 2.04) was observed for nematicidal toxicity of Cry5Ca1 and Cry5Da1, which is accordant with the phylogenetic results suggesting that domain II of the two novel Cry5 toxins evolved into two independent clades. Through comparison of the depressed degree of toxicity in the β-methylgalactoside detoxification test, we found that the novel toxin Cry5D possesses a different galactose-binding epitope; meanwhile, the finding that Cry5D does not share a motif (GXXXE) in the corresponding loop of domain II with Cry5B could explain the different galactose binding performance. Additionally, low-level cross-resistance of C. elegans bre mutant strains was evident between Cry5B and Cry5D. These results suggest that Cry5D can be used as an alternative to delay the potential resistance of nematodes to Cry5B.IMPORTANCE Although proper gene resources for Bt crops against the most serious agricultural pathogens, plant root-knot nematodes, are limited, we have identified two novel nematicidal toxins, Cry5Ca1 and Cry5Da1, against M. incognita, which have supplied more gene candidates for Bt crops designed against nematodes. Moreover, the association of the dissimilarity between Cry5Da1 and Cry5Ba1 and their low cross-resistance can be attributed not only to a low sequence similarity of domain II but also to the structural difference of the key motif and receptor-binding epitope in the loops. This association facilitates the selection of a proper candidate for the prospective design of pyramided Bt crops that can delay potential resistance.
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23
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Comparative Genomics of Bacillus thuringiensis Reveals a Path to Specialized Exploitation of Multiple Invertebrate Hosts. mBio 2017; 8:mBio.00822-17. [PMID: 28790205 PMCID: PMC5550751 DOI: 10.1128/mbio.00822-17] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Understanding the genetic basis of host shifts is a key genomic question for pathogen and parasite biology. The Bacillus cereus group, which encompasses Bacillus thuringiensis and Bacillus anthracis, contains pathogens that can infect insects, nematodes, and vertebrates. Since the target range of the essential virulence factors (Cry toxins) and many isolates is well known, this group presents a powerful system for investigating how pathogens can diversify and adapt to phylogenetically distant hosts. Specialization to exploit insects occurs at the level of the major clade and is associated with substantial changes in the core genome, and host switching between insect orders has occurred repeatedly within subclades. The transfer of plasmids with linked cry genes may account for much of the adaptation to particular insect orders, and network analysis implies that host specialization has produced strong associations between key toxin genes with similar targets. Analysis of the distribution of plasmid minireplicons shows that plasmids with orf156 and orf157, which carry genes encoding toxins against Lepidoptera or Diptera, were contained only by B. thuringiensis in the specialized insect clade (clade 2), indicating that tight genome/plasmid associations have been important in adaptation to invertebrate hosts. Moreover, the accumulation of multiple virulence factors on transposable elements suggests that cotransfer of diverse virulence factors is advantageous in terms of expanding the insecticidal spectrum, overcoming insect resistance, or through gains in pathogenicity via synergistic interactions between toxins.IMPORTANCE Population genomics have provided many new insights into the formation, evolution, and dynamics of bacterial pathogens of humans and other higher animals, but these pathogens usually have very narrow host ranges. As a pathogen of insects and nematodes, Bacillus thuringiensis, which produces toxins showing toxicity to many orders of insects and other invertebrates, can be used as a model to study the evolution of pathogens with wide host ranges. Phylogenomic analysis revealed that host specialization and switching occur at the level of the major clade and subclade, respectively. A toxin gene co-occurrence network indicates that multiple toxins with similar targets were accumulated by the same cell in the whole species. This accumulation may be one of the strategies that B. thuringiensis has used to fight against host resistance. This kind of formation and evolution of pathogens represents a different path used against multiple invertebrate hosts from that used against higher animals.
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Raymond B, Federici BA. In defense of Bacillus thuringiensis, the safest and most successful microbial insecticide available to humanity - a response to EFSA. FEMS Microbiol Ecol 2017. [PMID: 28645183 PMCID: PMC5812528 DOI: 10.1093/femsec/fix084] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The Bacillus cereus group contains vertebrate pathogens such as B. anthracis and B. cereus and the invertebrate pathogen B. thuringiensis (Bt). Microbial biopesticides based on Bt are widely recognised as being among the safest and least environmentally damaging insecticidal products available. Nevertheless, a recent food-poisoning incident prompted a European Food Safety Authority review which argued that Bt poses a health risk equivalent to B. cereus, a causative agent of diarrhoea. However, a critical examination of available data, and this latest incident, provides no solid evidence that Bt causes diarrhoea. Although relatively high levels of B. cereus-like spores can occur in foods, genotyping demonstrates that these are predominantly naturally occurring strains rather than biopesticides. Moreover, MLST genotyping of >2000 isolates show that biopesticide genotypes have never been isolated from any clinical infection. MLST data demonstrate that B. cereus group is heterogeneous and formed of distinct clades with substantial differences in biology, ecology and host association. The group posing the greatest risk (the anthracis clade) is distantly related to the clade containing all biopesticides. These recent data support the long-held view that Bt and especially the strains used in Bt biopesticides are very safe for humans.
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Affiliation(s)
- Ben Raymond
- University of Exeter, Penryn campus, Penryn, TR10 9FE, UK
| | - Brian A Federici
- Department of Entomology and Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA 92521 USA
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25
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Lone SA, Malik A, Padaria JC. Characterization of lepidopteran-specific cry1 and cry2 gene harbouring native Bacillus thuringiensis isolates toxic against Helicoverpa armigera. ACTA ACUST UNITED AC 2017. [PMID: 28649558 PMCID: PMC5472238 DOI: 10.1016/j.btre.2017.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Bacillus thuringiensis (Bt) based biopesticides are feasible alternatives to chemical pesticides. Here, we present the distribution of lepidopteran-specific cry1 and cry2 genes in native B. thuringiensis. Forty four out of 86 colonies were found to harbour crystals by phase contrast microscopy exhibiting a Bt index of 0.51. PCR analysis resulted in the amplification of cry1 in 24 and cry2 in 14 isolates. Twelve of the isolates showed presence of both cry1 and cry2, while 18 isolates did not show presence of either of the genes. Toxicity screening using spore-crystal mixtures against 2nd instar larvae of Helicoverpa armigera revealed that the isolates (50%) were either mildly toxic or not toxic (36.36%), and only 13.63% were toxic. The results are interesting, particularly so because the same isolates were previously reported to contain lepidopteran specific vip3A genes also, hence can complement the toxicity of the isolates harbouring vip3A genes.
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Affiliation(s)
- Showkat Ahmad Lone
- Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India
- Biotechnology and Climate Change Group, National Research Centre on Plant Biotechnology, New Delhi, India
| | - Abdul Malik
- Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh, India
| | - Jasdeep Chatrath Padaria
- Biotechnology and Climate Change Group, National Research Centre on Plant Biotechnology, New Delhi, India
- Corresponding author at: Biotechnology and Climate Change Group, National Research Centre on Plant Biotechnology (NRCPB), Pusa Campus, New Delhi, 110012, India.Biotechnology and Climate Change GroupNational Research Centre on Plant BiotechnologyNew DelhiIndia
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Bacillus thuringiensis: a successful insecticide with new environmental features and tidings. Appl Microbiol Biotechnol 2017; 101:2691-2711. [PMID: 28235989 DOI: 10.1007/s00253-017-8175-y] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 01/31/2017] [Accepted: 02/02/2017] [Indexed: 12/15/2022]
Abstract
Bacillus thuringiensis (Bt) is known as the most successful microbial insecticide against different orders of insect pests in agriculture and medicine. Moreover, Bt toxin genes also have been efficiently used to enhance resistance to insect pests in genetically modified crops. In light of the scientific advantages of new molecular biology technologies, recently, some other new potentials of Bt have been explored. These new environmental features include the toxicity against nematodes, mites, and ticks, antagonistic effects against plant and animal pathogenic bacteria and fungi, plant growth-promoting activities (PGPR), bioremediation of different heavy metals and other pollutants, biosynthesis of metal nanoparticles, production of polyhydroxyalkanoate biopolymer, and anticancer activities (due to parasporins). This review comprehensively describes recent advances in the Bt whole-genome studies, the last updated known Bt toxins and their functions, and application of cry genes in plant genetic engineering. Moreover, the review thoroughly describes the new features of Bt which make it a suitable cell factory that might be used for production of different novel valuable bioproducts.
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Du C, Cao S, Shi X, Nie X, Zheng J, Deng Y, Ruan L, Peng D, Sun M. Genetic and Biochemical Characterization of a Gene Operon for trans-Aconitic Acid, a Novel Nematicide from Bacillus thuringiensis. J Biol Chem 2017; 292:3517-3530. [PMID: 28087696 DOI: 10.1074/jbc.m116.762666] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/31/2016] [Indexed: 12/31/2022] Open
Abstract
trans-Aconitic acid (TAA) is an isomer of cis-aconitic acid (CAA), an intermediate of the tricarboxylic acid cycle that is synthesized by aconitase. Although TAA production has been detected in bacteria and plants for many years and is known to be a potent inhibitor of aconitase, its biosynthetic origins and the physiological relevance of its activity have remained unclear. We have serendipitously uncovered key information relevant to both of these questions. Specifically, in a search for novel nematicidal factors from Bacillus thuringiensis, a significant nematode pathogen harboring many protein virulence factors, we discovered a high yielding component that showed activity against the plant-parasitic nematode Meloidogyne incognita and surprisingly identified it as TAA. Comparison with CAA, which displayed a much weaker nematicidal effect, suggested that TAA is specifically synthesized by B. thuringiensis as a virulence factor. Analysis of mutants deficient in plasmids that were anticipated to encode virulence factors allowed us to isolate a TAA biosynthesis-related (tbr) operon consisting of two genes, tbrA and tbrB We expressed the corresponding proteins, TbrA and TbrB, and characterized them as an aconitate isomerase and TAA transporter, respectively. Bioinformatics analysis of the TAA biosynthetic gene cluster revealed the association of the TAA genes with transposable elements relevant for horizontal gene transfer as well as a distribution across B. cereus bacteria and other B. thuringiensis strains, suggesting a general role for TAA in the interactions of B. cereus group bacteria with nematode hosts in the soil environment. This study reveals new bioactivity for TAA and the TAA biosynthetic pathway, improving our understanding of virulence factors employed by B. thuringiensis pathogenesis and providing potential implications for nematode management applications.
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Affiliation(s)
- Cuiying Du
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Shiyun Cao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiangyu Shi
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Xiangtao Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yun Deng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Donghai Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070, China.
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Jurat-Fuentes JL, Crickmore N. Specificity determinants for Cry insecticidal proteins: Insights from their mode of action. J Invertebr Pathol 2017; 142:5-10. [DOI: 10.1016/j.jip.2016.07.018] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/02/2016] [Accepted: 07/28/2016] [Indexed: 12/17/2022]
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Nematicidal spore-forming Bacilli share similar virulence factors and mechanisms. Sci Rep 2016; 6:31341. [PMID: 27539267 PMCID: PMC4990965 DOI: 10.1038/srep31341] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 07/15/2016] [Indexed: 12/14/2022] Open
Abstract
In the soil environment, Bacilli can affect nematode development, fecundity and survival. However, although many Bacillus species can kill nematodes, the virulence mechanisms Bacilli utilize remain unknown. In this study, we collected 120 strains comprising 30 species across the Bacillaceae and Paenibacillaceae families of the Bacillales order and measured their nematicidal activities in vitro. Comparison of these strains’ nematicidal capacities revealed that nine species, including Bacillus thuringiensis, B. cereus, B. subtilis, B. pumilus, B. firmus, B. toyonensis, Lysinibacillus sphaericus, Brevibacillus laterosporus and B. brevis, were highly nematicidal, the first of which showed the highest activity. Genome sequencing and analysis identified many potential virulence factors, which grouped into five types. At least four possible mechanisms were deduced on the basis of the combination of these factors and the bacterial nematicidal activity, including a pore-forming mechanism of crystal proteins, an inhibition-like mechanism of thuringiensin and a degradation mechanism of proteases and/or chitinases. Our results demonstrate that 120 spore-forming Bacilli across different families share virulence factors that may contribute to their nematicidal capacity.
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Majed R, Faille C, Kallassy M, Gohar M. Bacillus cereus Biofilms-Same, Only Different. Front Microbiol 2016; 7:1054. [PMID: 27458448 PMCID: PMC4935679 DOI: 10.3389/fmicb.2016.01054] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/23/2016] [Indexed: 12/24/2022] Open
Abstract
Bacillus cereus displays a high diversity of lifestyles and ecological niches and include beneficial as well as pathogenic strains. These strains are widespread in the environment, are found on inert as well as on living surfaces and contaminate persistently the production lines of the food industry. Biofilms are suspected to play a key role in this ubiquitous distribution and in this persistency. Indeed, B. cereus produces a variety of biofilms which differ in their architecture and mechanism of formation, possibly reflecting an adaptation to various environments. Depending on the strain, B. cereus has the ability to grow as immersed or floating biofilms, and to secrete within the biofilm a vast array of metabolites, surfactants, bacteriocins, enzymes, and toxins, all compounds susceptible to act on the biofilm itself and/or on its environment. Within the biofilm, B. cereus exists in different physiological states and is able to generate highly resistant and adhesive spores, which themselves will increase the resistance of the bacterium to antimicrobials or to cleaning procedures. Current researches show that, despite similarities with the regulation processes and effector molecules involved in the initiation and maturation of the extensively studied Bacillus subtilis biofilm, important differences exists between the two species. The present review summarizes the up to date knowledge on biofilms produced by B. cereus and by two closely related pathogens, Bacillus thuringiensis and Bacillus anthracis. Economic issues caused by B. cereus biofilms and management strategies implemented to control these biofilms are included in this review, which also discuss the ecological and functional roles of biofilms in the lifecycle of these bacterial species and explore future developments in this important research area.
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Affiliation(s)
- Racha Majed
- Micalis Institute, INRA, AgroParisTech, CNRS, Université Paris-SaclayJouy-en-Josas, France; Unité de Recherche Technologies et Valorisation Alimentaire, Laboratoire de Biotechnologie, Université Saint-JosephBeirut, Lebanon
| | - Christine Faille
- UMR UMET: Unité Matériaux et Transformations, Centre National de la Recherche Scientifique, Institut National de la Recherche Agronomique, Université de Lille Villeneuve d'Ascq, France
| | - Mireille Kallassy
- Unité de Recherche Technologies et Valorisation Alimentaire, Laboratoire de Biotechnologie, Université Saint-Joseph Beirut, Lebanon
| | - Michel Gohar
- Micalis Institute, INRA, AgroParisTech, CNRS, Université Paris-SaclayJouy-en-Josas, France; Unité de Recherche Technologies et Valorisation Alimentaire, Laboratoire de Biotechnologie, Université Saint-JosephBeirut, Lebanon
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31
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Is There Sufficient Evidence to Consider Bacillus thuringiensis a Multihost Pathogen? Response to Loguercio and Argôlo-Filho. Trends Microbiol 2016; 23:587. [PMID: 26433691 DOI: 10.1016/j.tim.2015.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/12/2015] [Accepted: 08/13/2015] [Indexed: 11/21/2022]
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Bacillus thuringiensis Crystal Protein Cry6Aa Triggers Caenorhabditis elegans Necrosis Pathway Mediated by Aspartic Protease (ASP-1). PLoS Pathog 2016; 12:e1005389. [PMID: 26795495 PMCID: PMC4721865 DOI: 10.1371/journal.ppat.1005389] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/18/2015] [Indexed: 02/07/2023] Open
Abstract
Cell death plays an important role in host-pathogen interactions. Crystal proteins (toxins) are essential components of Bacillus thuringiensis (Bt) biological pesticides because of their specific toxicity against insects and nematodes. However, the mode of action by which crystal toxins to induce cell death is not completely understood. Here we show that crystal toxin triggers cell death by necrosis signaling pathway using crystal toxin Cry6Aa-Caenorhabditis elegans toxin-host interaction system, which involves an increase in concentrations of cytoplasmic calcium, lysosomal lyses, uptake of propidium iodide, and burst of death fluorescence. We find that a deficiency in the necrosis pathway confers tolerance to Cry6Aa toxin. Intriguingly, the necrosis pathway is specifically triggered by Cry6Aa, not by Cry5Ba, whose amino acid sequence is different from that of Cry6Aa. Furthermore, Cry6Aa-induced necrosis pathway requires aspartic protease (ASP-1). In addition, ASP-1 protects Cry6Aa from over-degradation in C. elegans. This is the first demonstration that deficiency in necrosis pathway confers tolerance to Bt crystal protein, and that Cry6A triggers necrosis represents a newly added necrosis paradigm in the C. elegans. Understanding this model could lead to new strategies for nematode control. Necrosis contributes to many devastating pathological conditions, such as neurodegenerative diseases and microbial pathogenesis. Bacillus thuringiensis crystal proteins are effective biopesticides. Our study reveals that B. thuringiensis Cry6Aa protein triggers the necrosis pathway using Caenorhabditis elegans as a model. We show that aspartic protease ASP-1 is required for Cry6Aa protein-induced necrosis, whereas intrinsic insults induce necrosis mediated by ASP-3 and ASP-4. Our findings contribute to the understanding of the mechanism of Bt crystal protein action and host-pathogen interactions. Because necrosis mechanisms are conserved from nematodes to humans, the fact that necrosis can be induced by Cry6Aa provides a model system for studying necrosis mechanisms in human diseases.
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33
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Peng D, Lin J, Huang Q, Zheng W, Liu G, Zheng J, Zhu L, Sun M. A novel metalloproteinase virulence factor is involved in Bacillus thuringiensis pathogenesis in nematodes and insects. Environ Microbiol 2015; 18:846-62. [PMID: 26995589 DOI: 10.1111/1462-2920.13069] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 09/25/2015] [Indexed: 11/29/2022]
Abstract
The Gram-positive soil bacterium Bacillus thuringiensis has been developed as the leading microbial insecticide for years. The pathogenesis of B. thuringiensis requires common extracellular factors that depend on the PlcR regulon, which regulates a large number of virulence factors; however, the precise role of many of these proteins is not known. In this study, we describe the complete lifecycle of a nematicidal B. thuringiensis strain in the free living nematode Caenorhabditis elegans using in vitro and in vivo molecular techniques to follow host and bacterial effectors during the infection process. We then focus on the metalloproteinase ColB, a collagenase, which was found highly important for destruction of the intestine thereby facilitates the adaptation and colonization of B. thuringiensis in C. elegans. In vivo green fluorescent protein (GFP) reporter-gene studies showed that ColB expression is highly induced and regulated by the global activator PlcR. Finally, we demonstrated that ColB also takes part in B. thuringiensis virulence in an insect model following injection and oral infection. Indeed, addition of purified ColB accelerates the action of Cry toxin proteins in insects, too. These results give novel insights into host adaptation for B. thuringiensis and other B. cereus group bacteria and highlight the role of collagenase metalloproteases to synergize infection process.
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Affiliation(s)
- Donghai Peng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jian Lin
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qiong Huang
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Wen Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Guoqiang Liu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Jinshui Zheng
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Lei Zhu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Ming Sun
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
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Milutinović B, Höfling C, Futo M, Scharsack JP, Kurtz J. Infection of Tribolium castaneum with Bacillus thuringiensis: quantification of bacterial replication within cadavers, transmission via cannibalism, and inhibition of spore germination. Appl Environ Microbiol 2015; 81:8135-44. [PMID: 26386058 PMCID: PMC4651099 DOI: 10.1128/aem.02051-15] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 09/14/2015] [Indexed: 12/18/2022] Open
Abstract
Reproduction within a host and transmission to the next host are crucial for the virulence and fitness of pathogens. Nevertheless, basic knowledge about such parameters is often missing from the literature, even for well-studied bacteria, such as Bacillus thuringiensis, an endospore-forming insect pathogen, which infects its hosts via the oral route. To characterize bacterial replication success, we made use of an experimental oral infection system for the red flour beetle Tribolium castaneum and developed a flow cytometric assay for the quantification of both spore ingestion by the individual beetle larvae and the resulting spore load after bacterial replication and resporulation within cadavers. On average, spore numbers increased 460-fold, showing that Bacillus thuringiensis grows and replicates successfully in insect cadavers. By inoculating cadaver-derived spores and spores from bacterial stock cultures into nutrient medium, we next investigated outgrowth characteristics of vegetative cells and found that cadaver-derived bacteria showed reduced growth compared to bacteria from the stock cultures. Interestingly, this reduced growth was a consequence of inhibited spore germination, probably originating from the host and resulting in reduced host mortality in subsequent infections by cadaver-derived spores. Nevertheless, we further showed that Bacillus thuringiensis transmission was possible via larval cannibalism when no other food was offered. These results contribute to our understanding of the ecology of Bacillus thuringiensis as an insect pathogen.
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Affiliation(s)
- Barbara Milutinović
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Christina Höfling
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Momir Futo
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Jörn P Scharsack
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
| | - Joachim Kurtz
- Institute for Evolution and Biodiversity, University of Münster, Münster, Germany
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The Two Lives of Bacillus thuringiensis: Response to Ruan et al. and Loguercio and Argôlo-Filho. Trends Microbiol 2015; 24:1-2. [PMID: 26602444 DOI: 10.1016/j.tim.2015.10.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/19/2015] [Accepted: 10/23/2015] [Indexed: 12/24/2022]
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36
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Zambrano Moreno DC, Bonilla Buitrago RR, Avellaneda L, Zambrano G. Análisis prospectivo de los bioinsumos agrícolas en Colombia: una consulta a expertos. REVISTA COLOMBIANA DE BIOTECNOLOGÍA 2015. [DOI: 10.15446/rev.colomb.biote.v17n2.48472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
<p><strong>Título en ingles: Prospective analysis of agricultural bioinoculants in Colombia: an expert consultation</strong></p><p>La productividad y sostenibilidad de la agricultura en Colombia pueden ser influidas positivamente a través del aprovechamiento de la biodiversidad para la producción de bioinsumos. Fueron analizados a mediano y largo plazo, los posibles escenarios futuros generados por las regulaciones que intervienen en el avance tecnológico de los bioinsumos, a través de la aplicación de una encuesta Delphi, con la participación de 23 expertos, teniendo en cuenta las tres dimensiones del desarrollo sostenible. Sobre la base de este estudio, se encontró que el 65% de los expertos consideran que el impacto de la innovación o el desarrollo tecnológico del uso de bioinsumos en la producción agrícola, tiene un alto impacto económico con un nivel de concordancia significativo (≥0.05). Adicionalmente, el 65% seleccionó como el mejor escenario, en el cual se den condiciones que promuevan mayor desarrollo, acceso y aplicación de los bioinsumos, de tal forma que se incremente el ritmo de incorporación de la tecnología por parte de los productores. En conclusión, más allá del nivel de desarrollo tecnológico, es necesario revisar los procesos legislativos para la comercialización de los bioinsumos, fue evidente que el éxito futuro de la industria de la producción de productos biológicos dependerá de la gestión de empresas innovadoras, la eficiente comercialización de los mismos, la educación y transferencia a los productores y el progreso de la investigación.</p>
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Ruan L, Wang H, Cai G, Peng D, Zhou H, Zheng J, Zhu L, Wang X, Yu H, Li S, Geng C, Sun M. A two-domain protein triggers heat shock pathway and necrosis pathway both in model plant and nematode. Environ Microbiol 2015; 17:4547-65. [PMID: 26147248 DOI: 10.1111/1462-2920.12968] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 06/24/2015] [Indexed: 11/30/2022]
Abstract
The entomopathogen Bacillus thuringiensis is equipped with multiple virulent factors. The genome sequence of B. thuringiensis YBT1520 revealed the presence of a two-domain protein named Nel which is composed of a necrosis-inducing phytophthora protein 1-like domain found in phytopathogens and a ricin B-like lectin domain. The merging of two distantly related domains is relatively rare. Nel induced necrosis and pathogen-triggered immunity (PTI) on model plants. The Nel also exhibited inhibition activity to nematode. Microscopic observation showed that the toxicity of Nel to nematodes targets the intestine. Quantitative proteomics revealed that Nel stimulated the host defence. The Nel thus possesses dual roles, as both toxin and elicitor. Remarkably, the Nel protein triggered a similar response, induction of the heat shock pathway and the necrosis pathway, in both model plants and nematodes. The unusual ability of Nel to function across kingdom suggests a highly conserved mechanism in eukaryotes that predates the divergence of plants and animal. It is also speculated that the two-domain protein is the result of horizontal gene transfer (HGT) between phytopathogens and entomopathogens. Our results provide an example that HGT occurs between members of different species or even genera with lower frequency are particularly important for evolution of new bacterial pathogen lineages with new virulence. Bacillus thuringiensis occupies the same ecological niches, plant and soil, as phytopathogens, providing the opportunity for gene exchange.
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Affiliation(s)
- Lifang Ruan
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Huihui Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ge Cai
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Donghai Peng
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Hua Zhou
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jinshui Zheng
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lei Zhu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xixi Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Haoquan Yu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Seng Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ce Geng
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Ming Sun
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
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38
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Loguercio LL, Argôlo-Filho RC. Anthropogenic action shapes the evolutionary ecology of Bacillus thuringiensis: response to Ruan et al. Trends Microbiol 2015; 23:519-20. [PMID: 26163434 DOI: 10.1016/j.tim.2015.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/18/2015] [Accepted: 06/12/2015] [Indexed: 01/30/2023]
Affiliation(s)
- Leandro L Loguercio
- Department of Biological Sciences (DCB), State University of Santa Cruz (UESC), Ilhéus-BA, Brazil.
| | - Ronaldo C Argôlo-Filho
- Department of Biological Sciences (DCB), State University of Santa Cruz (UESC), Ilhéus-BA, Brazil
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